This book teaches mathematical structures and how they can be applied in environmental science. Each chapter presents story problems with an emphasis on derivation. Linear and non-linear algebraic equations, derivatives and integrals, ordinary differential equations, and partial differential equations are the basic kinds of structures, or mathematical models, that are discussed. For each of these, the discussion follows the pattern of first presenting an example of a type of structure as applied to environmental science. Next the definition of the structure is presented. This is usually followed by other examples of how the structure arises in environmental science, then the analytic methods of solving and learning from the structure are discussed. This is followed by teaching numerical methods for use when the situation is difficult. In most cases, examples of using Matlab software to solve and explore the structures are also included.